We propose to continue the Harvard/Brown Anxiety Research Project (HARP), a unique, naturalistic, prospective, multicenter study of 711 subjects with anxiety disorders, who were enrolled when seeking treatment at mental health outpatient settings, for an additional 5 years of f/u. This will enable us to obtain a minimum of 15 years of f/u on subjects and to incorporate new assessments and data analysis methods in order to address important unanswered questions and develop a more comprehensive picture of the longitudinal course and outcome of common anxiety disorders: panic disorder with and without agoraphobia, generalized anxiety disorder, and social phobia. Enrollment of African-American and Hispanic subjects with anxiety disorders during the first three years of this proposal will enable us to obtain a representative sample and to examine the clinical characteristics, longitudinal course, and course mediators, in unstudied ethnic minority populations. Our specific aims are to 1) examine patterns, predictors and psychosocial outcomes of anxiety course; 2) examine factors associated with the clinical course of anxiety disorders in an aging population; 3) describe somatic and psychosocial treatment received and investigate the mediating effect of somatic treatment on course; 4) examine the course of anxiety disorders in African-Americans and Hispanics; and 5) examine the utility of dimensional approaches in characterizing and understanding the nature and course of the anxiety disorders and comorbid depressive disorders. Subjects will be evaluated at annual intervals with instruments that obtain detailed information on symptom status and severity, diagnostic status, treatment received, psychosocial functioning, stressful life events, and other domains. We have added a new assessment that will allow us to examine the effects of anxiety disorders on medical disorders and disability. We have also incorporated new data analysis methods to take maximum advantage of the new data. HARP is unique in its large number of subjects, comprehensiveness of assessment, and length of prospective f/u. This proposal will obtain meaningful new knowledge about anxiety disorders as described in a substantial revision of previous aims and hypotheses using new findings from HARP and other investigators during the past 4 years. Continuation of HARP should shed new light on clinically and theoretically important, innovative questions about a group of common and impairing disorders that have not been adequately addressed by previous research, particularly within African-Americans and Hispanics.